Ahh,Don't Feel Stupid Frenchie ;-)
It's Means We Americans Will Defend Ourselves From Home Grown Tyrants And Foreign Invaders.
Some History
The flag is named after American general and politician Christopher Gadsden (1724–1805), who designed it in 1775 during the American Revolution. It was used by the Continental Marines as an early motto flag.
https://en.m.wikipedia.org/wiki/Gadsden_flag